$(document).ready(function(){    
    $("#Mul > li > a").click(function () {
		//找到主菜单项对应的子菜单项
		var ulNode = $(this).next("ul");
		ulNode.slideToggle();
		changeIcon($(this));
	});
});

/**
 * 修改主菜单的指示图标
 */
function changeIcon(mainNode) {
    if (mainNode) {
        
	    if (mainNode.css("background-image").indexOf("M_li2.jpg") >= 0) {
	        mainNode.css("background-image", "url('/Areas/AdminMrg/Content/adminImg/M_li3.jpg')");
		} else {
	        mainNode.css("background-image", "url('/Areas/AdminMrg/Content/adminImg/M_li2.jpg')");
		}
	}
}
